Surface broaching machines



Unite States atent p 1 1 3,537,354

[72] Inventor Benjamin A. Veazey v [56] References Cited gf gy England UNITED STATES PATENTS 1 PP 1684140 9/1928 Perkinsetal. 90/92 Wed Oct-3111968 2,251,154 7/1941 Nenningeretal. 90/63 [45] Patented Nov.3,l970

[73] Assignee The Lapointe Machine Tool Company FOREIGN PATENTS Limited 152,370 1962 U.S.S.R. 90/92 Otterspool walfordbypass watt-0rd Primary Examiner-Gil Weidenfeld E f England Attorney-Roberts, Cushman & Grover a British Company ABSTRACT: A machine for broaching nonplanar surfaces on workpieces, in which a plurality of broach bodies resiliently [54] i fg fl q MACHINES secured to the tool slide and carrying teeth, the pitch of which rawmg is greater than the length of the surface to be machined, are [52] US. Cl 90/91 reciprocal relative to the tool slide towards and away from a [51] Int. Cl 823d 41/04 workpiece on the work fixture by cooperating cam and fol- [50] Field ofSearch 90/92,9l, lower means on the breach bodies and the work fixture 93, 63, 43 respectively.

SURFACE BROACIIING MACHINES This invention relates to the surfacebroaching of nonplanar surfaces on workpieces and its object is to provide a machine which will broach such surfaces in a single operation.

To this end, according to the invention, there is'provided a surface-hroaching machine comprising a tool slide operating in a straight line. a broach body resiliently secured to said tool slide and carrying teeth the pitch of which is greater than the length of the surface to be machined, a work fixture upon vwhich a workpiece can be clamped in fixed relation to said tool slide, and cooperating means on said work fixture and said broach body for reciprocating said body in a plane transverse to the plane of movement of said tool slide in controlled relation to the movement of each successive tooth past a workpiece on said fixture.

In a preferred form of the invention the broach body carries a vertically extending cam track for engagementwith cam follower means on the work fixture.

A machine constructed in accordance with the invention is illustrated in the accompanying drawings in which:

FIG. I is a view partly in plan and partly in horizontal section of the work fixture and part of the tool slide of the machine;

FIG. 2 is a vertical section on an enlarged scale, through the forward end of the work fixture;

FIGS. 3 and 4 are a horizontal section and an elevation, on an enlarged scale of an alternative form of roller mounting on the fixture;

FIGS. 5 and 6 are a front and side elevation respectively, on an enlarged settle, ol'tlie upper end ol'tltc tool slide;

l'ltl. 7 is a sectltm. on the line Vll- Vll of FIG. 5;

MG. 8 is a section, similar to FIG. 7, showing an alternative connection between a broach body and the tool slide;

FIG. 9 is a vertical section, on an enlarged scale, through the junctions between the broach bodies and the tool slide at a point near the vertical center line of the machine; and

FIGS. 10 and 11 are views similar to FIGS. 5 and 6 showing an alternative form of broach body.

The main elements of the machine are of conventional design and will not, therefore, be described'in detail.

A work fixture 1 having a central shuttle 2 in which a workpiece (not shown) can be hydraulically clamped in conventional manner is provided'on each side with forwardextensions 3 which are pivotally mounted at 4 in side members 5 of a fixed frame 6. Rotatably mounted in each forward extension 3 is a pair of rollers 7 which project rearwardly into a gap 8 between each extension and the forward end of the fixture I.

. Projecting forwardly into the gaps 8 opposite the rollers 7 are rollers 9 rotatably mounted in carriers IO'slidably arranged in sleeves II and connected by rods 12 to plungers of hydraulic reaction cylinders I3 supplied with fluid throughr-st-andpipes I4 from a source (not shown). Pressure supplied to the cylinders l3 acting against the inner ends of the rods 12 located within the cylinders yieldably holds the rollers 9 against the pathways 20. In a'modification each roller 9 may be replaced by a pair of rollers IS-(FIGS. 3 and4.) rotatably mounted in a yoke 16 which. ispivotally mounted at I7 on the forward end of a carrier 18 which is connected to the" cylinder 13in the same manner aseach carrier 10. The rollers 7 and the rollers 9' or engage cam tracks l'9and roller pathways 20 respectively provided on eachof a vertical. series of broach'bodies 2-1 resiliently secured to-a subbase 23 which-is rigidly secured-to a tool slide 24 vertically reciprocable in a part (not shown) of the machine frame 6. Yielding engagement of the rollers 9 with the pathways 20 causes the broach body 21 to'move'in and out relative'to the work in the work holder in accordance with the profiles of the cam tracks 19L As shown in FIG. 5,

each broach body 21 carries three broach teeth-25-secured= thereto by plug clamps 26and as shown'in FIG. 6apeak 27 of each cam track registers with a tooth 25'and' a trough 28*occurs between adjacent teeth. Each roller pathway ZO i's'for-med' witha plateau portion29eoextensive with the broach teeth 25 and a dwell portion 30:at the upper and lower end of each broach body. In the modification shown in FIGS. 10 and 11 each broach body 21 is provided with three pairs of broach teeth 31 each pair of which is arranged to act simultaneously on opposite sides of a workpiece. In this construction also the peaks 27 of each cam track coincide with pairs of the teeth and the troughs 28 occur between adjacent pairs of teeth. In this case also each roller pathway on the uppermost broach body is provided with the same configuration as each cam track. As shown in FIGS. 5. 6. II and I2 each broach body 21 is formed with apertures 22 for the receipt ofthe means shown in either FIG. 7 or FIG. 8 for resiliently connecting the broach body to the subbase 23. Each connecting means comprises a bush 31a which enters and aperture 22 and is provided with a flange 32 which is secured to the breach body by screws 33. a shoulder screw 34 which enters athreaded aperture 35 in the subbase 23-and a compression spring 36. In the form shown in FIG. 7 the spring 36 acts between ashoulder 37on the bush 31a and the surface of the subbase 23, whereas in the form shown in FIG. 8 the spring acts between a shoulder 38 on the bush and a washer 39 on the screw 34. The siibbase 23 is provided at intervals with stop blocks 40 which project into recesses 41 formed at the upper and lower e'rids of each broach body 21 and engage radius blocks 42 on each broach body. Each broach body is also provided with r'adius'guides 43 engaging surfaces 44'on the subb'ase 23 and secured to the broach body by screws 44 (FIG. 9). Inter'p'osed between the guides 43 and the surface 45 of the subbase 23 is a pad 46 which is secured to each broach body by screws 47 passing through'thc guides 43.

During lltc working stroke of the tool slide 24 each broach body. in its passage past a workpiece secured on thel'lxlure l is individually reciprocated towards and away from the work piece in accordance with theprofile of the cam tracks 19 to provide the desired form ofcut on the workpiece and the body is maintained in a correct upright position relative to the workpiece and the subbase by the engagement between the radius members 42 and 43 on the block and the cooperating surfaces on the subbase.

Iclaim:

l. A surfac'e-broachin'g machine comprising a tool slide operating in a straight'line, a broach body resiliently secured to said tool slide and carrying teeth the pitch of which is greater than the length of the surface to be machined,"a work fixture upon which a workpiece can be clamped in fixed relation to said tool slide, and cooperatingmea'ns on said work fixture and said broach body for reciprocating said body in a plane transverse to the plane of movement of said tool slide in controlled relation to the movement of each successive to'oth pasta workpiece on said fixture.

2. A machine according to claim I, wherein said cooperating meanscomprises a vertically extending cam track on said broach body and cam follower means-on saidwork fixture.

3'. A machineaccording to claim I, wherein said broach body is provided with a centrally located row of broach teeth extending in thc direction ofmovem'ent of said tool slide and a camtr'ack on each side oland extending parallel to said row of broach teeth and said work fixture is provided with camfollower means for engagement with eachcam track.

4. A machine according to claim'3', wherein said cam'tracks are provided on the surface of said earn body oppositeto that 'of said teeth-, and said cam follower means is provided in forward extensions of said work fixture which extend-around the side edges-of-said broach body.

5. A machine according to claim 4, wherein said cam follower means comprises rollers mounted for rotation about fixed horizontal axes insaid forward extensions of said work fixture. s v

6. A machine according to claim 4', wherein the main body of said work fixture is provided with antifriction means for engagement with the surface'of said broach body carrying said broachteethat points opposite said cam-tracks.

7L Amachine'according to claim 6; wherein said antifriction means comprises rollers rotatably mounted on carriers slidable rearwardly in said work fixture against the action of hydraulic pressure.

base rigidly secured to said tool slide.

11. A machine according to claim 1, wherein a plurality of broach bodies are resiliently secured one above the other to said tool slide and individually reciprocable relative to the tool slide and work fixture during operative movement of said tool slide.

12. A machine according to claim 1, wherein cooperating means are provided on said broach body and said tool slide for maintaining said broach body correctly positioned relative to said workpiece. 

